1. Field of the Invention
The present invention relates to a circuit device, a circuit module, and an outdoor unit, and in particular, relates to a circuit device, a circuit module, and an outdoor unit in which a hybrid integrated circuit formed on an upper face of a circuit board is sealed with a case member.
2. Description of the Related Art
In recent years, newspapers report environmental destruction, signs of global warming, and the causes of the warming. One of various causes for the warming is an increase in electricity consumption. The generation of electricity depends largely on the exhausting oil, and the burning of the oil causes the problem of the emission of the carbon dioxide gas into the atmosphere. Another cause of the warming is automobiles, most of which use gasoline for fuel.
The electricity is absolutely necessary for operating the electronic equipments existing all over the world. The electricity serves as the power source for the electronic equipments such as a washing machine, an air conditioner, and a mobile device, and is indispensable for human beings living on the earth to maintain a cultural life, and thus the increase in electricity consumption is an issue difficult to solve.
Meanwhile, automobiles have been more sophisticated in functionality, by achieving, for example, the teleconference made therein, the guidance to a destination by a car navigation system, cooling by a car air conditioner, and clearly and brightly illuminating by headlights. The consumers all over the world have been competing in purchasing such automobiles. Unlike in the old days, driving the automobile while using various functions in the vehicle interior results in an increase in energy consumption eventually.
The same is true of computers and mobile phones. In order to achieve these functions, semiconductor devices, the so-called power element, IC and LSI, are employed, and these components are mounted on a substrate, such as a printed circuit board for example. The substrate is then mounted on a set of electronic equipments. Considering this aspect, a reduction in electricity consumption is a very important subject also for the semiconductor devices.
Such electronic equipments, particularly, the semiconductor devices generate heat during its own operation. As the temperature of an active region increases, the driving capability decreases. More energy has been consumed with the increase of the driving capability.
Accordingly, the electricity consumed by a semiconductor device itself needs to be reduced by releasing the heat of the semiconductor device to the outside in a certain way. A power MOS device capable of power driving is an example of the devices that are most likely to exhibit the tendency of the increased temperature, and needs to release the heat with an innovative way. For the purpose of releasing the heat, in the devices, such as an inverter module used in a washing machine, a refrigerator, and the like, and in a driver module used in a plasma display, a metal substrate has been frequently mounted recently.
The surface of the metal substrate is covered with an insulating resin or the like, a conductive pattern is formed thereon, and the elements required for the inverter circuit for example, are electrically connected to, and mounted on the conductive pattern.
The configuration of a hybrid integrated circuit device 150 employing a case member 111 is described with reference to FIG. 15. The hybrid integrated circuit device 150 includes: a substrate 101 made of a metal, such as aluminum; an insulating layer 102 formed so as to cover the upper face of the substrate 101; a conductive pattern 103 formed on the upper face of the insulating layer 102; and a circuit element 110 such as a transistor electrically connected to the conductive pattern 103. Then, the circuit element 110 is sealed with the case member 11 and a sealing resin 108.
Specifically, the case member 111 has an approximately frame-like shape and is in contact with the side face of the substrate 101. In addition, in order to secure a sealing space over the upper face of the substrate 101, the upper end part of the case member 111 is positioned above the upper face of the substrate 101. Then, the sealing resin 108 is filled in the space surrounded by the case member 111 above the substrate 101 so as to cover the circuit element 110 such as a semiconductor element. With this configuration, the circuit element incorporated on the upper face of the substrate 101 can be sealed with a sealing resin 108 being filling in the space surrounded by the case member 111, even if the substrate 101 is relatively large.
This technology is described for instance in Japanese Patent Application Publication No. 2007-036014.
In the hybrid integrated circuit device 150 described above, a power transistor, such as an insulated gate bipolar transistor (IGBT), and a driver IC for driving this power transistor are mounted on the upper face of the substrate 101. In addition, a controlling element, such as a microcomputer for controlling this driver IC, is mounted on the mounting substrate side on which the hybrid integrated circuit device 150 is mounted. Because of this configuration, the area required to mount a circuit which controls for driving a load, such as a motor, has to be large on the mounting substrate side.
In order to solve the above-described problem, provided is a method in which the microcomputer is fixed, for example, to the upper face of the substrate 101 together with the above-described power transistor or driver IC. This configuration allows the power transistor and the microcomputer to be incorporated into one hybrid integrated circuit device, thereby requires smaller area for mounting the control circuit. However, if the power transistor and the microcomputer are fixed to the upper face of the same substrate 101, a heat generated in the power transistor is conducted to the microcomputer via the substrate 101 made of a metal such as aluminum. In addition, the heat generated in the power transistor is conducted to the microcomputer via the sealing resin 108 for sealing the entire device. As a result, the microcomputer heated by the power transistor might cause a misoperation.
Additionally, the operation of an air conditioner is controlled by a circuit module attached to the outdoor unit thereof. Since being installed in the outside, the outdoor unit is exposed to a considerably high temperature. Accordingly, this condition causes a crack or the like in the electrically connected portion of the circuit module, and therefore, a countermeasure for releasing, to the outside, the heat generated in the circuit module is required.